The EPO published Regeneron Pharmaceuticals' patent application EP4367231A1 covering methods of treating skin cancer with histidine ammonia-lyase (HAL) agonists. The patent claims therapeutic uses of HAL enzyme agonists for cancer treatment (A61P 35/00), composition claims (A61K 38/51, A61K 31/03), and related diagnostic methods (G01N 33/50). The application designates all 31 European extension states including major markets.

Pharmaceutical companies developing enzyme-based oncology therapies should conduct freedom-to-operate analyses to assess potential infringement risks from these claims. Biotech firms and researchers working on histidine metabolism pathways or HAL-related treatments should review the specific claim scope to determine whether licensing or design-around strategies are necessary.